Your computer isn't relevant... Only the ammount of memmory 8gigs and the processor quad core intel count. Next to that the soundcard is very very very important offcourse..
Also i use Linux for the multi Asio solution
I use : (most of this under Wine)
Live styler
Ableton live
Q-ranger (just toying around)
As base of my sound i use NI Complete, with some lovely sample libraries added to Kontakt.
and various Vst's that i mainly use for solo stuff.
I have an old 88 key weighted Viscount Masterkeyboard and a 61 key Edirol from Roland
I dont think you will find many software setrups here, Rikki Bears has tried it and only Frank L Rosenthal is a die hard software setup fan.
If you arent an experienced Linux sysadmin or programmer i would not choose Linux as it requires a lot of scripting to get these things running.
I am on the verge of returning back to hardware arrangers, with VBSt's only added for solo stuff, nothing works out of the box and through its fun making things work... Just playing a song straight working right out of the box is fun too..
I think for me a full software solution is not yet ideal, i have come to see that a TOTL arranger with full midi master capabillities as the base of my system will be better for me.